PSL301H1 Lecture 9: L9 Electrical Signals, Blood Flow, & Cardiac Cycle

• School: UTSG
• Department: Physiology
• Course: PSL301H1
• Professor: Michelle French

Document Summary

Lecture 9 electrical signals, blood flow, and cardiac cycle. Cardiac action potential to aortic flow: summary: electrical signals originate in the sa node, and are propagated throughout the heart. Cardiac cycle: sequences of events that occur when the heart beats. Two phases of the cardiac cycle: (1) diastole: ventricles are relaxed (2) systole: ventricles contract: overall aim: understand and integrate electrical activity, contraction, and blood flow in and out of the heart. Contraction-relaxation cycle generates pressure gradients: results in orderly movement of blood, blood flows from high pressure low pressure. Events on the right and left sides of the heart are the same, but pressures are lower on the right. Right side does(cid:374)"t (cid:374)eed to ge(cid:374)e(cid:396)ate high p(cid:396)essu(cid:396)e (cid:271)e(cid:272)ause pulmonary circuit is(cid:374)"t pul(cid:373)o(cid:374)a(cid:396)(cid:455: muscle on the right side of the heart is weaker. Left side has to use high pressure to feed the high pressure systemic circuit. For the pump to work effectively, we need stages of contracting and relaxing.